The challenge of discovering beneficial viruses.

The most important effect of viruses on the human body is to cause infectious diseases. A number of serious diseases in humans are the result of viral infection, including influenza, haemorrhagic fever, severe acute respiratory syndrome (SARS) and acquired immunodeficiency syndrome (AIDS). Deaths from infectious viral diseases make up a large proportion of those worldwide from human disease. Some viruses are recognized in the aetiology of non-infectious conditions, including inflammation, cancers and other life-threatening diseases. Even though many recent studies on new antiviral approaches focused on vaccines and RNA interference technology, and have obtained promising outcomes, newly identified human viruses, such as Ebola virus (Bermejo et al., 2006), SARS-CoV (Tsang et al., 2003), Nipah virus (Bellini et al., 2005) and H5N1 highly pathogenic avian influenza virus (Oner et al., 2006), are continually found. These create serious challenges to worldwide public health. Therefore, new strategies are needed to counteract pathogenic viruses.